1. Field of the Invention
The invention relates to electrophotographic apparatus having selectable magnification of the document image. More particularly, it relates to apparatus of that type having a number of lenses or other optical elements which are differentially movable into the optical path in response to the operator's selection of a particular magnification.
2. Description of the Prior Art
Electrophotographic apparatus with selectable magnification of the document image is known, but is subject to production of poor copies if operated in a careless or uninformed manner.
At the time of image projection during a reproduction cycle, if the projection magnification is changed by mistake, there results a movement of the optical system and as a consequence the reproduced copy thus obtained is of no use. Likewise, if a reproducing-projecting cycle is carried out by mistake during a change in the projection magnification, then a photosensitive paper or the like is wasted. Accordingly, it is desirable to provide means for preventing such an erroneous operation or error in workmanship.